Purification of hydrogen halides



paented Nov. 15, 1938 Y r .7 Y 2,137,095

UNITED 'sTA Es- PATENT IOFFICET PURIFICATION OF HYDROGEN HALIDE S- Edward B. Peck, Elizabeth,"N. J., assignor to Standard Oil Development Company, a conic-' I ration of Delaware 1 No Drawing. Application December 24, 1936,

. Serial No. 117,538

4 Claims. (01*. 23-152) This invention relates to thepurification of hyaction takes place and in many instances cooling drogen halides. More specifically, it concerns the must be resorted to. The gas may be dried prior purification of hydrogen halides which contain to or after this treatment. The contacting may free halogen impurities. also be carried out in a. bubble'plate tower or 5 Hydrogen halides such as hydrogen chloride mixer such as a turbo-mixer, of suitable corrosion '5 (I-ICL) have for some time been considered as resistantmaterial. The time of contact employed commercial waste products and very little efiort varies with the type of oil employed, andis genwas spent toward their purification. Within reerally inthe neighborhood of 0.2 to 5 seconds. cent years, however, a number of chemical proc- This invention is not limited by the specific esses have been developed wherein pure hydrogen illustrations nor by any mechanism of operation,, 10

chloride may be employed as a raw material for but only by the following claims in which the further syntheses. For example, olefines such as intention is to cover the invention as broadly as ethylene may be combined with hydrogen chlothe prior art permits. I

ride in presence of catalysts to give high yields of I claim:

alkyl halides. 1. The method of removing free halogen im- Unfortunately, much of the commercially purity from hydrogen halidescontaining not subavailable by-product hydrogen chloride is constantially more than of free halogen which taminated with free halogen such as chlorine, comprises contacting the mixture in gaseous which interferes with the reaction of the halide form with a liquid cracked petroleum oil having 20 and likewise has a tendency to destroy the a high flash point and containing substantial 20 catalyst. I quantities of unsaturated hydrocarbons, at a tem- It is an object of this invention to effectively reperature substantially below the flash point of move such halogens, regardless of whether they the oil. are present in low concentrations, say 0.1% or 1% 2. The method of removing free halogen imor in high concentrations in the neighborhood of purity f ydro e a es c n i ng not Sub 25 10 or 20% or more. By such a step it is possible stantially more than 20% of free halogen which to prepare a substantially pure hydrogen chloprises contacting t m xture in gaseous form ride-containing gas suitable for the preparation with a liquid crackedpetroleum oil having a flash of alkyl chlorides, etc. point above 300 F. and containing substantial This object is attained by scrubbing the hydroquantities of unsaturated hydrocarbons, at a tem- 30 gen chloride-containing gas with a liquidhydro- D a e ot Sub y above 00 F. carbon material having a low volatility and a 3. e method of removing free o ne imsubstantially high flash point. The treatment espurity from hydrogen chloride containing not pecially suited for this purpose comprises counsubstantially more than 20% of free chlorine tercurrent contacting of the impure hydrogen which comprises contacting the mixture in gase- '35 chloride-containing gas with a closely fractionous-form with a liquid cracked petroleum oil havated petroleum oil having a viscosity of less than ing a flash point above 300 F. and containing 45 seconds Saybolt at 210 F. This may be done substantial quantities of unsaturated hydrocarat r m mp r ures or at pera ures in the bons, at a temperature not substantially above 40 range of 0-200 F; It is also preferableto em- 200 F, 40

ploy an Oil 'f a fl h Point about 4. The method of removing free chlorine im- Q the yp Of 0118 Whlch y be 6111111051611, the purityv from hydrogen chloride containing not highly cracked products such as cycle gas oil, substantially more than 20% of free chlorine cracking coil tar fractions, etc., are preferred, alhi h comprises contacting t mixture in gasethough highly aromatic fractions such as S02, ous form with a liquid cracked petroleum oil havphenol, or other solvent petroleum extracts, diing a flash point above 300 F. and a viscosity of phenyl, diphenyl oxide, and similar aromatic by less than 45 seconds Saybolt Universal at 210 F.

drocarbons may be used. and containing substantial quantities of unsatu- The treatment consists generallyin passing the rated hydrocarbons, at a temperature of 0 to chlorine-containing hydrogen chloride through a 200 F. 50

tower filled with ceramic contact material over EDWARD B. PECK.

which is trickled the oil described above. A re- 

